Wireless sensor network (WSNs) are considered as suitable solution for long-time and large-scale outdoor environmental monitoring. However, an important feature that distinguishes the WSNs from traditional monitoring systems is their energy constraints. In fact, these nodes have often limited and usually not replenish able power source. Therefore managing these limited and precious resources is a key challenge. In this paper we use an optimization scheme based on adaptive modulation and power control for a green routing protocol. The optimization mechanism is subject of certain QoS requirement in term of total end-to end delay time and bit error rate. The simulation results show that the proposed algorithm can reduce the consumed energy of the sensor nodes.